含紧固件复合材料层压板雷击后损伤及力学性能退化试验

Test on damage and mechanical property degradation of composite laminate with fastener subjected to lightning strike

以含金属紧固件编织结构碳纤维/环氧树脂复合材料层压板为研究对象,通过人工模拟雷电流试验,并结合目视观察、超声损伤扫描、微米X射线三维成像及高倍显微镜等损伤检测手段,对其在雷电流直接效应作用下的损伤模式、机制及特征进行了分析,同时,采用材料力学性能试验系统,对其雷击后的静拉伸承载能力退化程度进行了评估。研究结果表明:由金属紧固件引起的"雷电流分散效应"导致含紧固件复合材料层压板雷击损伤以分层损伤为主,且损伤沿层压板整个厚度方向分布;雷击损伤的产生存在一个雷电流强度门槛值,当雷电流强度小于该值时,层压板不会出现损伤;紧固孔周围的雷击损伤在静拉伸过程中会产生"应力分散效应",导致含紧固件层压板静拉伸承载能力随雷击峰值电流的增加先提高后下降。

Artificial lightning strike testing was performed on a series of carbon woven fabric/epoxy laminate with metal fastener,and damage was assessed using visual inspection,ultrasonic testing,micro X-ray inspection and high-power microscope to analyze the damage mode,damage mechanism and damage characteristic of composite laminate with metal fastener under lightning current direct effect,meanwhile,mechanical property degradation extent of composite laminate with metal fastener was also assessed using material mechanical property test system.Research results indicate that due to the lightning current distributing effect aroused by mental fastener,delamination is the mainly damage mode of composite laminate with metal fastener when subjected to lightning strike,and it is distributed along the whole thickness direction of laminate.There is a lightning current intensity threshold about whether composite laminate with metal fastener occurs lightning strike damage,and when the lightning current intensity is lower than it,composite laminate with metal fastener will not appear lightning strike damage.During the process of static tension,because lightning strike damage around fastener hole will arouse the effect of stress distribution,the tensile loading capacity of composite laminate with metal fastener with lightning strike damage increases first and then decreases with the increasing lightning peak current.